Heading away from Larison's Corner (US 206 at NJ 15, where CR 565 begins), there is no way of knowing if this is a state- or county-erected shield, but I have my guess.

Northbound, this is the only embossed sign with this message left, though even the "new" ones (non-reflective, of course) on NJ 23 and NJ 284 look the same.

Oh, Rt. 565 is also Glenwood Road, and for a region where other counties (Passaic, Morris, and Bergen) hardly ever use county route shields, it's strange that Sussex County chooses to only post the number.